In the event your device can no longer access data, there are a few things you should check.
Make sure you are not in airplane mode, as this will prevent any active data connection that isn’t Wi-Fi.
Verify that your Wi-Fi Network has a current, and active Data connection.
Try connecting your device to another Wi-Fi Network to verify that it is not a network issue.
Turn off Wi-Fi connection and determine if your device is receive Cellular Data connection.
If your Cellular Data is also unavailable, reboot the device and try again.
Make sure that your Cellular Data is active by reaching out to your service provider.